Means for switching booster-transformers.



W. ZEDERBOHM.

MEANS FOR SWITCHING BOOSTER TRANSFORMERS.

APPLICATION FILED 001. 19, 1911.

Patented June 24, 1913.

CL Z,

UNITED STATES PATENT OFFICE.

WILLY ZEDERBOHM, CHARLOTTEN'BURG, GERMANY, ASSIGNOR T0 SIEMENS- SCHU'CKERT-WERKE, G. M. B. H. OF BERLIN, GERMANY, A CORPORATION OF GERMANY.

'UEANSE FGR. SWITCHING BOOSTER-TRANSFORMERS.

Specification of Letters Patent.

Patented June 24, 1913.

Application flied October 19, 1911. Serial No. 655,85.

To all'whom it may concern:

Be it known that I, WILLY ZnDERBonM, a subject of the German Emperor, and residing at Charlottenburg, near Berlin, Germany, have invented certain new and useful Improvements in Means for Switching Booster-Transformers, of which the following is a specification.

My invention relates to means for switch ing booster transformers into and out of circuit. x

In order to regulate the voltage in an alternating-current system use is frequently made of booster transformers whose one winding is connected in series with the mains while the-other or exciting winding is connected acrossv the mains of the machinesor system. Phase shifting transformers are frequently employed for this purpose. In order that the system may be readily supervised and maintained it is preferable to arrange the booster transformers so that they may be completely separated from the system. There are, however, considerable 'difiicu'lties in bringing about this separation during the operation of the system. If the series, windings are first short-circuited by a conductor in order afterward to remove them from lthe system by means of switches, a short-circuitis made endangering the apparatus itself and reducing the voltage of the system to zero. If, on the contrary, the exciting windingis disconnected first, the' series winding exercises a choking action on the current in the system ahd brings about a considerable fall of voltage.

The principal object of my invention is to provide means for readily and safely disconnecting booster transformers from, and connecting the same to the system. One illustrative embodiment of the invention' is represented as-an example inthe accompanying drawing, in more or less diagrammatical fashion.

In the drawing the series windings of the phase shiftin transformer. T .are denoted with 2 an the exciting windings are denoted with e. The series windings may be thrown between the line wires or and the bus bars s by means of switches t Besides a direct connection mav be established between theline and the bus bars by closing switch it This latter switch, however, is open when the booster transformer t is in operation.

The form which the booster transformer t has in this arrangement is in itself known in the art and frequently designated as a so-called phase shifting transformer in which the exciting winding is disposed on a rotor and the secondary winding on a stationary core. The rotor may be oscillated through a. suitable angle whereby the phases can be shifted any desired-degree. In this particular case the rotor is diagrammatically re resented by the exciting winding an is disposed on a shaft g which may be operated in any well known manner, for instance, bythe worm drive m actuated by the crank is. At the other end of shaft g are provided three slip rings r to each of which one end of the three exciting windings e is-connected, while the other ends of the exciting windings are connected together so thatthe exciting winding is connected in Y connect-ion. On the slip rings r glide brushes f which are connected with the three-pole switch It, the contacts a of which are connected with the line wires n. The phase as previously stated being adjustable, its value, or in turn the value of the booster tension in the windings z may be adjusted at will relatively to the .lineftension, It is of course understood that the inacnner in which the two windings of the transformer are shifted relatively to each other is ent-irely immaterial in the present invention and the construction shown is only meant to represent an example.

The three-pole switch It has three contacts a b, c for each lever .h. All contacts 0 are electrically connected with each other. Thecontacts fa and b of each section are connected with each other by a resistance w. Moreover each of the contacts ais connected with one of the three line wires n. I

It may now be assumed that, the switch u is closed so that the line is directly connected with the bus bars and it may also be assumed that switches t are open so that the transformer is out, of operation. In

.order to throw the transformer into the line,

first the three levers h which are mechanically coupled by means of bar d are thrown to the right and onto their contacts 0 as shown,whereby the exciting windings 0 transltn'mer lac ng still short circuited the booster tension of windings 2 is still zero.

.\'ow three-pole switch It is thrown on to ings a a re connccted-witl'i the line over the resistance w and upon further movement it! the switches :h" in'the same direction onto their contacts athe exciting winding e" is directly connected with the line wires nli Now the boostenwindings "2" throw betweenthe line tension and the tellSit'm at the bus bars a boosting tension the phase of which may be'adjusted at will by shifting the exciting windings erelatively to the booster windings a as described above. Since nowthe line tension is added to or nected in series with said mains, and an eX- contact pieces,' a resistance connected lac-- Itween said contaets and a third Contact, its l lltttt'ftf l-b whereby the exertingv windsubtracted from the tension of the windings 2, the tension ofthe bus bars a may be the a mount of the booster tension in the windings 2'. In order'to- .disconnect the booster transformer the sequenceof the above described operations is reversed. First threepole switch It is thrown" onto its contacts c in-onier to first'short circuit the excit ingwindings whereupon switch u is closed and switches fl are opened.

said third contacts being all electric:i'll connected together,'sa1d switches being meehant cally interconnected to permit when the exciting winding of the transforgner is being diseonnectedg trom the system, first the con-- necting of thereststancesbetween the mains and thc'exciting windii'ig, thereupon the disconnecting of the exciting winding from the system and its simultaneous short ci'rcuiting toprevent indu'ctiveiaction of the booster transformer upon the system and. to permit separation of-theseries winding from the system. 7

Q. In an alternating current system, the

coinbination with bus bars, mains and a varied relatively toth'e line tenswn double;

. The described arrangen'ient"may of course i be e'm loyed not only in the case of phase shifting bo ister-'traiisfottncrs which were speciallymentioned in the introduction, but also in the 'easc of. stationary transformbooster transformer having a series and an exciting winding, and means for connecting said series winding in'series. with and disconnecting same from' said bus bars and mains, a system of switches each having a switch lever connectedfiwith "the"e.\"citing winding, a bank ofco act piecesyandarcsistance connectedfbetween the first; two-of the contact'piecesj-thelastcontact pieces of the switches being-connected together, and

the first contact pie'ce"ofeaeh switchbeing 1 connected to said mains.

ers with and without regulation by stepj :ovitelrtS.

w I claim: I

l. In an alternating current system the combination with the mains, of a booster tr ansforn'ier having a series winding con- In testimony whereof I "havesigned my name to this specification inth'epresence oftwo witnesses. e

' WILLY ZEDERBOHM.

\Vitnesses: i I

HENRY Unseen, Vt 'oiiommn Haur'r. 

